'Robe worn by the Omenkillers, butchers of twisted conscience. Its thick apron is worn in remembrance of Rollo, the progenitor of the Omenkillers and a perfumer of antiquity.' The Omenkillers are the Lands Between's quiet sanitation order. Born of the Erdtree's flat refusal to recognise the Omen as souls deserving of grace, they exist to cull the horned children that the orthodoxy cannot afford to name. Rollo, their progenitor, was a famous perfumer in antiquity, the canon's perfumers being the original breath-and-air theologians, who later branched into mystics and warriors. Rollo's branch became butchers.

'Ashen remains in which spirits yet dwell. Use to summon the spirit of Omenkiller Rollo. Spirit of Rollo, known as the first Omenkiller. Once a famous perfumer, Rollo imbibed a physick to rid himself of emotion, thus enabling him to enact his nightmarish labor, hunting the Omen.' The technical solution was chemistry. Rollo brewed a wondrous physick that erased emotion from the drinker's body. The Omenkillers who follow him drink it before each cull. The thick leather apron is the order's remembrance of his name. The mask, Omensmirk Mask, is carved with the smirking face of an elder evil, the same evil-spirit ancestors that the Omen children themselves see in their nightmares. The killer wears the nightmare's face. The cursed child sees their tormentor as the inside of their own dreams.